1. Field of the Invention
The subject invention is directed to portable fire extinguishers, and more particularly, to a portable fire extinguisher having a discharge valve with a flexible hermetic seal, along with a visual pressure indicator.
2. Description of Related Art
Discharge valves used on stored pressure portable fire extinguishers have a pressure indicator to monitor interior pressure during storage, and a stem to control the flow of a pressurized fire extinguishing agent during discharge. The pressure indicator is periodically inspected to ensure that the fire extinguisher is fully pressurized and ready for use in the event of a fire. Bourdon tube type pressure indicators have been utilized in fire extinguishers for decades, as disclosed for example in U.S. Pat. No. 3,815,421.
Bourdon tube type pressure indicators are expensive to fabricate and provide potential leak points within the discharge valve. These potential leak points exist at the connection between the bourdon tube and the valve body, as well as in the tube itself, which can develop cracks resulting from the flattening, coiling and welding processes used during manufacture.
It would be beneficial therefore, to provide a portable fire extinguisher with a pressure indicator that is less expensive and less susceptible to leaks than typical bourdon tube type pressure indicators to monitor pressure within the fire extinguisher during storage. It would also be beneficial to eliminate the potential leak point at the piston that controls flow during activation. During storage the piston is in a closed position to retain pressure. Imperfections or contamination at its sealing surfaces can result in leakage.